(Topic ID: 143359)

Sega whitestar reset (SST)

By dri

8 years ago


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#1 8 years ago

I have an SST that I can play for hours on its own without any issues. When I boot up my entire game room this game reset intermittently. My B/W games have the kahr.us reset protection otherwise my TZ on the same circuit will reset like crazy too.

I live in a rental and don't have much saying about the wiring in the house. The SST is on a brand new circuit that was wired when I moved in.

Anyone have had similar problems? I'm going to check the 5V circuitry and might rebuild the entire thing as outlined here: http://www.pinwiki.com/wiki/index.php?title=Data_East/Sega#Low_5VDC_and_game_resets

#2 8 years ago

I forgot if my LWJP had the reset issue....it was a long process of fixing etc, but its a 20 yr old board/game so I shipped the boards out and had them repaired. First test with a DMM to see what voltage you get at the test points. If that 5v isn't up to par, then ya, you may want to rebuild that.

#3 8 years ago

Couple things to do. Measure DC voltage at the bottom of R114 on the power driver board. This is the +5V test point. If it's low, then adjust the voltage up using the potentiometer at R115.

There is a connector that goes from the top of the power driver board up to the bottom of the CPU board. It sits right above a voltage regulator and the heat can cause the pins to tarnish. Try reseating the connector at both ends first. If it helps for a few weeks, then probably best to replace the headers and connectors.

#4 8 years ago

Thanks for the pointers. My 5VDC showed 5.08 at R114. I ran the game on its own and I could easily trigger a reset by hitting all three flippers. In other words the problem had gotten worse. At some resets I could see that voltage drop about .1V. I upped the pot to 5.10VDC and the game remained on and survived TZ having a LITZ running on the same circuit.

I did measure the 5VDC of the MPU to get a difference. Before reseating the connectors it read 4.95VDC and afterwards 5.03VDC. I have reflowed every pin on the powerdriver board a year or so ago but I guess this will be coming back from time to time.

Is it safe to run the game at 5.10VDC if it works for now?

#5 8 years ago

Need to replace header plugs and pins that take 5v. That has fixed 4 or 5 different machines that have exactly the issue describe

2 weeks later
#6 8 years ago
Quoted from robm:

Need to replace header plugs and pins that take 5v. That has fixed 4 or 5 different machines that have exactly the issue describe

Hey, thanks for the tip. Do you know any vendor that sell these in kits? What are the plugs called if I need to get them separately?

#7 8 years ago

www.greatplainselectronics.com
Look up the .156 24-pin breakaway headers.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

#8 8 years ago

oh man I'm gonna try the tips in this thread. I have a super nice SST with a similar reset issue. Can't wait to get it 100%

#9 8 years ago

holy crap, found my notes from LWJP resetting. I'll paste them in. Hope they help.

4.4 Low +5VDC and Game Resets

The +5VDC for logic power is sourced from the 8VAC secondary windings on the transformer. The 8VAC is fed to the I/O Power Driver Board, and rectified via bridge rectifier, BRDG21. The rectified DC voltage is regulated via an LM338K adjustable voltage regulator. Logic voltage can be adjusted via R116 on the driver board, which is a 50 ohm adjustment potentiometer.

U413, which is located on the CPU / sound board next to the reset button, is a Dallas Maxim DS1232 monitoring chip. In theory, should the logic voltage dip to less than 5% or +4.75VDC, the DS1232 will force a reset of the CPU. However, it has been determined that most White Star board sets will not function properly below +4.85VDC.

If the voltage on the power I/O driver board is below the +4.85VDC threshold, adjustment can be made via the R116 adjustment pot, until a satisfactory voltage is achieved. The best location to measure the +5VDC is at the bottom leg of resistor R114. R114 is located in the vicinity of the R116 adjustment pot, and just below the +5VDC LED, L2. If a satisfactory voltage cannot be achieved, turn the game off. Remove connector J16, located above the LM338 regulator. Turn the game back on, and measure the +5V again. If a satisfactory voltage can be acquired with J16 disconnected, a board or component which uses the +5VDC is "dragging" it down. Turn the game off, and remove all 5V input connectors on all other boards at this time. Reconnect J16 again, and review the logic voltage on the I/O Power Driver board. Repeat the process of turning off the game, and reinstalling logic power connectors one at a time to determine the suspect board. Keep in mind that all opto switch receivers used throughout the game use the same +5VDC logic lines. If no other boards in the backbox appear to be suspect, an opto transmitter board may be at fault.

Should the game start randomly resetting, the first course of action is to measure the +5VDC on the I/O Power Driver Board. If the logic voltage is within spec., measure the +5VDC on the CPU / sound board. The +5V test point on the CPU / sound board is located just to the left of the 6809EP CPU chip (U209) on the board. If the voltage drastically differs between the measurement of the I/O Power Driver Board and the CPU / sound board, turn the game off. Remove and reseat connections CN2 on the CPU / sound board and J16 on the I/O power driver board.

4.4.1 Game Resets with DMD Controller Board Connected

This may be a bit of an anomaly, but it is worth mentioning. If when the DMD controller board is connected without the data line ribbon cables, and the game continues to reset, replacement of BRDG21 may be required.

In one particular instance, a game was resetting continually with only the +5v / ground connection connected to the DMD controller board. If the board was not connected, the driver board would output ~+5VDC. If the DMD controller board was connected, the driver board's logic line would dip down to around +4.85VDC. Logically speaking, this type of symptom somewhat points to the DMD controller board having issue. However, the end result was replacement of BRDG21 per Stern tech support.

It is worth mentioning that the bridge rectifier did test correctly (using a DMM in diode test) both in circuit and out of circuit, but these tests were conducted while the bridge was not under load.

#10 8 years ago
Quoted from northvibe:

oly crap, found my notes from LWJP resetting. I'll paste them in. Hope they help.

Your notes are from the PinWiki. See:
http://www.pinwiki.com/wiki/index.php?title=Sega/Stern_White_Star_Repair#Low_.2B5VDC_and_Game_Resets

--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

#11 8 years ago

They are! I saved them in a word doc on an old computer. Just booted it up and found it. I didn't mean to claim I wrote them, just that I took them and put them in a document for my "notes" on the sega reset issue. I also forgot where I had found them.

Thanks for putting in the source!

hahah, the link was always in your signature I should'a known

#12 8 years ago
Quoted from northvibe:

hahah, the link was always in your signature I should'a known


--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

1 year later
1 month later
#14 7 years ago

Had a reset of on a Whitestar Monopoly repair for a client today. Appreciate this thread, made it easy as just now running into reset issues with Whitestar board sets as they age. Sure enough, voltage was good on I/O but only 4.93 on CPU. CN2 was a little brittle feeling, so I repinned with molex .156 and brought up to 4.99, adjusted R116 slightly to 5.04 on CPU and good to go!

#15 7 years ago
Quoted from The_Director:

Had a reset of on a Whitestar Monopoly repair for a client today. Appreciate this thread, made it easy as just now running into reset issues with Whitestar board sets as they age. Sure enough, voltage was good on I/O but only 4.93 on CPU. CN2 was a little brittle feeling, so I repinned with molex .156 and brought up to 4.99, adjusted R116 slightly to 5.04 on CPU and good to go!

Glad you posted your issue and fix too!

1 year later
#16 6 years ago

On my Sharkey’s Shootout, the voltage at R114 leg was a solid 5.05 and 5.04 during several games with all flippers engaged and multi ball’s flying. It turned out to be the two IDC connectors above the heat sink on the driver board, and the IDC connector at the bottom of the CPU sound board right above those (all circled in red). They were heat stressed and dried out and plastic had broken off the outsides of connectors. I replaced them with Molex connectors with trifercon pins. Have not replaced the pins on PCB boards yet but no problems after weeks and several hours of use. Between that heat sink and flourecent light bulb, this is a common problem.

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